Vaisala, a global leader in environmental and industrial measurement, has launched a new Vaisala Energy Budget Outlook service to provide independent assessment of the impact of weather on wind portfolio performance. The launch comes amid increased demand from wind energy operators for tools to more accurately forecast revenue, and for the ability to adjust these forecasts based on recent wind performance.

Typically, pre-construction estimates of wind speeds and actual energy production figures are used to forecast a site or portfolio's energy production (energy budget). This new service provides a range of information on how more recent anomalies in wind speeds will affect an individual project or a wider portfolio. In doing so, it allows wind energy operators to more accurately set project budgets for the coming months.

For instance, wind anomaly maps released by Vaisala show that in May, much of the United States suffered abnormally low wind speeds. The trend continued across many regions in June, but key wind generation states such as Texas and Oklahoma saw a reversal in fortunes. These fluctuations highlight the scale of the challenge operators face in financial planning.

Cumulative under- or over-performance will have a significant impact on annual operating and financial results, may contribute to surprise shifts in project value, and potentially have damaging effects both on shareholder value and investor confidence.

While abnormal wind speeds are regularly cited as a leading cause of underperformance in wind energy operators' financial reports, isolating and accurately quantifying their effects remains difficult. The Vaisala Energy Budget Outlook service is designed to tackle this financial uncertainty, by offering wind energy operators greater flexibility and increased accuracy, allowing them to re-calibrate their energy budgets on a rolling, monthly basis.

"Wind farm operators increasingly want to understand the impact of all factors affecting performance - including the weather," said Pascal Storck, Director of Renewable Energy at Vaisala. "In the absence of reliable data on its effects on performance, many operators have been attributing any unexplained budget anomalies to weather variation. However, for the purposes of financial reporting in particular, it is clear that a greater level of detail is needed."

"Just labelling unexplained differences as weather impacts isn't helpful," said Storck. "The point is how are you going to deal with them? The Vaisala Energy Budget Outlook is an easy means of pinpointing and addressing some of the financial impact that resource fluctuations create."